Fuel for internal combustion engines



Se t. 14, 1937. A. c. G. EGERTON 2,093,008

- FUEL FOR INTERNAL COMBUSTION ENGINES Filed June 20, 1935" INLET MANIFOLD ENGINE CARBURETTOR COMBUSTION INJECTOR CHAMBER INJ ECTOR CYLINDER Patented Sept. 14, 1937 UNITED :STATES PATENT OFFICE FUEL roa m'rnamu. COMBUSTION ENGINES Alfred Charles Glyn Egertomflxford, England Application June. 20, 1935, Serial No. 27,608

In Great Britain June 29, 1934 I 2 Claims.

bustion is impeded. This invention aims at overcoming these clifliculties.

In an earlier publication (Supplement to Nature, July 7th, 1928) dealing with Engine knock 1 and related problems certain hypotheses are advanced in relation to the initial combustion in a compressed mixture of gaseous fuel and air, viz. that a temporary peroxide is formeda per; oxide in a high energy state. Reference is also 20 made to a reaction chain mechanism in which aldehydes may be formed from such peroxides. In that publication the possible formation of these oxygenated bodies was being considered as explanatory of the phenomenon of knocking. Experiments have now been carried out with fuels which exhibit the phenomena of difficult ignition or delayed combustion and it is found that alkyl or acyl peroxides (which give rise to knocking in an engine using a normal mixture of petrol and air) are effective both in accelerating ignition and promoting combustion; the com- .pounds employed in the present invention are such that on decomposition they yield oxygenated free radicals (which, it is believed, facilitate ignition and promote combustion of the fuel) and are of the type in which one of the peroxide oxygen atoms is attached to an alkyl or acyl radical, while the other peroxide oxygen atom is attached either to a hydrogen atom, or to a second alkyl or acyl radical.

According to this invention, a method of accelerating the ignition and/or promoting the combustion of fuel in an internal combustion engine which consists in introducing a peroxide into the combustion chamber, is characterized in that there is employed an alkyl or acyl peroxide of the type above specified.

The peroxides of the type above mentioned are referred to in the claims as peroxides of the series hereinbefore specified.

The invention further includes a fuel for use in internal-combustion engines, particularly those of the compression-ignition type, which consists in admixing with fuel a small propor-' 55 tion say one per cent. of an alkyl or acyl peroxide of the type above specified such, for ex ample, as diethyl peroxide. The hydroxyperoxides in general are not so effective as the normal peroxide. v

It will be understood that the addition of these peroxides to a fuel which is normally satisfactory would give rise to knocking and is to be avoided.-

The following represent the main types of peroxides which might be met with as peroxidized products of aliphatic hydrocarbons:-

monobydroxy-alkyl peroxide dielkylmonohydroxy peroxide dialkyldihydroxy peroxide acyl peroxide the fuel a small proportion, say about 1%, of diethyl peroxide.

The following are tests which were carried out on a compression-ignition engine with various fuels showing the effect of the addition of a small proporiton of diethyl peroxide (referred to in the tables as D. E. P.). The engine was first run on a good Shell Diesel oil giving smooth running and a fairly good exhaust. The fuel feed was then so arranged that a creosote oil, to which 1.8% by weight of diethyl peroxide had been added, could be fed to' the pump. Under the same conditions of load, the running of the engine was fairly smooth and the exhaust was only just visible and was not pungent. The running of the engine under similar conditions on the creosote oil without the addition of diethyl peroxide was very rough and the exhaust gases were rather pungent. The conditions for these three comparative tests were:--

Table I Pump set- Fuel R. 1. M. ting B. M. E. P.

Diesel Shell S. G. .874 1,500 26 E 93. 5 Creosote oil+l.8% D. E. P--. l, 200 26 E 93. 5 Creosote oil 1, 200 26 E 93. 0

Diagrams were taken in each case under the following conditions Thus the addition of diethyl peroxide to the fuel greatly improvedits combustion.

A more severe test was next carried out on the fuel. The engine was first motored at 1800 R. P. M. for 3 minutes with the fuel cut off, and was then idled at 1800 R. P. M. Under these conditions only a good fuel will take up without missing or giving a bad exhaust. With the undoped creosote, the engine missed badly and the exhaust was smoky and blue with a pungent smell affecting the eyes badly. Whereas, with the some fuel doped with 1.8% diethyl peroxide there was no missing and the exhaust was 800d, being clear and having little effect on the nose or eyes.

Tests at smaller dilutions were not carried out,-

'28. M. E. P. first on Miri (non waxy) fuel alone,

and then with the same fuel doped with 2% diethyl peroxide. The engine did not run well on the undoped oil.

difficult to start an internal-combustion engine owing to a lack of the conditions essential to the initiation of ignition, there may be introduced into the starting mixture (e. g. into the float chamber of the carburettor) a small proportion of an organic peroxide of the kind referred to.

Figures 1 and 2 are diagrammatic representations of a'fuei supply system for internal combustion engines in which organic peroxides are to be used in the manner hereinbefore set forth.

Figure 1 is a diagrammatic representation of an internal combustion engine having a fuel tank i connected by a fuel supply pipe 4 to the carburettor, a tank 2 containing the organic peroxide is connected by means of a branch pipe 8 to the fuel supply pipe 4 which branch pipe is provided with a control cock shown at 0 whereby the supply of the organic peroxide may be cut off as desired. The carburettor is attached in known manner to the inlet manifold of the engine and the fuel having dispersed therein the organic peroxide is conveyed to the carburettor, and thence passes through the induction system and inlet manifold to the combustion chamber in the usual manner.

Figure 2 is a diagrammatic representation of an internal combustion engine of the compression ignition type wherein a fuel tank I is connected by Table III Fuel R. r. M. B. M. E. r. we Remarks Miri 1500 29 E. 90. 6 855 lbs/El Rate of pressure rise 22.810!

some delay Miri +2% Di E. P -l.. 1500 29 E. 81(7) 800 lbs/El Deilnite improvement in combustion. Rate of preesure rise 10 B Miri 1500 29 E. 90 Moms/El (*Average, the torque changed due to air trapped in feed.)

As well as the marked improvement in the diagram, the engine ran much quieter on the doped fuel and the exhaust improved.

Similar tests at slightly retarded injection to give later burning were carried out on Shell Diesel (M. G.) oil, with and without diethyl peroxide,

there was perhaps a slight improvement in the combustion but no appreciable change in torque. The smoothness of running was good in both cases. The maximum pressure is the'flring com- These trials have shown that indifferent fuel oils can be greatly improved by the addition of diethyl peroxide.

In another practical example, where it is found a fuel supply pipe 4 to the injector pump; a tank 2 containing an organic peroxide is connected by means of a branch pipe 8, a fuel supply pipe 4, and is provided with a control cock 3 for controlling the supply of the organic peroxide. The fuel, which may contain a small proportion of the organic peroxide is fed to the injector and forced through the injector nozzle into the combustion chamber whereby the organic peroxide may be dispersed in said combustion chamber to facilitate the combustion of the fuel or to accelerate the ignition of the fuel.

Iclaim:--

1. A Diesel fuel oil, comprising a hydrocarbon fuel having added thereto a small proportion of a dialkyl peroxide which will lower the spontaneous ignition temperature and shorten the delay period of ignition similar to diethyl peroxide and in which the two alkyl groups are united solely by the peroxide oxygen atoms.

2. A fuel according to claim 1, wherein said dialkyl peroxide is diethyl peroxide.

ALI 'RED CHARLES GLYN EGERTON. 

